UPDATE: We just got a response from them. They are not open for rent, so this is no longer an option.

I estimate that stage to be no more than 35' in diameter. Under Hue's opinion, it may not be as awesome because the audience would be separated from the competitors, and there may not be simultaneous cypher space. 30-35' may be enough though, given it is even that big.

Commons Hotel - Meridian Ballroom (second page)
I think this may be the ideal size we are shooting for, with a capacity of 600. Price however, is unknown. Their site is annoying to navigate, so I'm not even sure if this information is provided or if we need to inquire personally. For those who remember the Dance Marathon, this is the room.